At present, the majority of global energy is generated by burning mineral substances such as petroleum or coal. However, such mineral substances are by no means inexhaustible energy. If people rely on burning mineral substances to generate energy, presumably in the near future, the world will come to an energy crisis. In addition, burning mineral substances will also produce considerable CO2 or CO or other gases, affecting the ozone concentrations in the atmosphere. It will increase the average temperatures of the earth, deteriorating the greenhouse effect. Thereby the ice sheet in the North and the South Poles will melt gradually, rising the sea level. It not only reduces the living spaces of humans, but also affects the subsistence of marine organisms. Moreover, reduced ozone concentrations in the atmosphere also lead to incomplete absorbency by the atmosphere of ultraviolet (UV) rays radiated from the sun. Hence, humans tend to get skin cancer if exposed to the UV rays frequently. It not only endangers the ecosystem but also affects human health.
In order to solve current energy crisis, many countries develop actively various types of renewable energy such as wind energy, solar energy, geo-heat energy, and tide energy. Taking wind energy for example, as long as the sun and the earth revolute continuously, the wind power will be inexhaustible. By driving generators by winds, wind energy is converted into electric energy. In the conversion process, no CO2 and any other pollutants will be produced. Accordingly, many countries, such as Denmark, Netherlands, Germany, and the United States, devote themselves into their researches. Normal wind-power generators are comprised of such components or equipments as blades, gearboxes, and generators. Not only the structure and size of the blades but also the capacity of the generators influence the quantity of input wind energy. If the generators themselves consume considerable energy, then extractable electric energy must be quite limited.
Please refer to FIG. 1, wherein a rotor of a permanent-magnet generator is described in Taiwan's patent number 262,607. As shown in the figure, the generator rotor according to the prior art includes a yoke 10, a shell 20, a plurality of magnets 30, and a cover 40. The shell 20 is adapted in the yoke 10; the magnets 30 are adapted in the shell 20; and the cover 40 is adapted in the shell 10. The shell 10 is a cylinder. A containing space 12 is adapted in one side of said cylinder, while a penetrating bore is adapted on the other side of said cylinder. The shell 20 is adapted in the containing space 12, and is a ring. A plurality of spacing bars 22 is adapted with intervals between, and is adapted in an extending manner on one side of the ring. The magnets 30 are adapted between adjacent spacing bars 22. The cover 40 is a hollow body. A composite element 42 is adapted on one side of said cover 40. A through hole 423 is adapted on the composite element 42. When the cover 40 is adapted in the yoke 10, the composite element 42 is adapted on the bottom of the containing space 12 such that the penetrating bore 14 is aligned with the through hole 423. Meanwhile, the shell 20 and the magnets 30 are adapted on the outer sidewall of the cover 40.
However, the length of the magnets 30 in the prior art is short, therefore the electric power generated via induction by the generator is limited. Moreover, the rotor has its own weight; thereby it has its own moment of inertia. The more the weight of the rotor, the greater its moment of inertia is. Correspondingly, the greater the moment of inertia of the rotor, the lower the efficiency of conversion from wind power to electric power is. If the electric power induced by the generator can be increased and the efficiency of conversion from wind power to electric power can be enhanced, it is for sure that the power generated by the generator can be increased. In addition, the rotor structure in the prior art is difficult to assemble. It is also quite laborious to change components of the rotor structure.
Accordingly, the present invention provides a generator rotor structure, which is able not only to increase the electric power induced by the generator, but also to reduce the weight and, in turn, the moment of inertia of the rotor such that the power generated by the generator is enhanced. Besides, the assembly is so simple that the assembly efficiency is increased. Thereby, the problems described above can be solved.